/Engine/Source/Developer/CollectionManager/Public/ICollectionManager.h
Checks whether any collections have a custom color set, optionally retrieving the list of in-use colors
true if there are any custom colors in use, false otherwise.
bool HasCollectionColors ( [TArray](API\Runtime\Core\Containers\TArray)< [FLinearColor](API\Runtime\Core\Math\FLinearColor) > * OutColors ) const